For the treatment of strains and sprains of joints, ligaments, tendons and muscles, the most commonly recommended treatment involves rest, ice, compression and elevation. A tenet of this treatment is that the sooner the treatment is started, the more effective it is.
Presently, cold treatment devices are available which utilize a variety of cooling and compression means including, for example, endothermic chemical packs and ice packs which may be held in place with elastic bandages and elaborate refrigerated water circulation systems.
Devices including ice packs and endothermic chemical packs have been frequently employed as they may be applied immediately. However, the ice is usually at a temperature of 28.degree. F. or less, and may freeze the tissue causing frostbite. Also, the elastic bandages which are often used to secure these packs in place provide uneven compression and can cut off blood flow. In addition, as the ice melts, the pressure is reduced and the pack may slip out of position. Thus, this system requires close supervision to insure that the patient is properly and safely treated.
The equipment required for the refrigerated water circulation systems is so bulky that these systems are usually employed in a hospital or training room hours after the injury has occurred. This water circulation equipment is very expensive, complex and requires constant monitoring by the person providing care.
Ideally, doctors recommend that treatment be given for only 20 minutes at a time and that the pressure be limited to 0.4 psi over ambient and applied uniformly over a broad area, thereby preventing restriction of the blood circulation while adequately immobilizing the injured area. In addition, doctors recommend that cold be limited to no less than 36.degree. F. for the 20 minute period and that both pressure and cold be uniformly applied during the treatment.
A prior device which provided portable, immediate cold and compression therapy is shown in U.S. Pat. No. 3,871,381. However, this device has several inherent drawbacks. This device is based upon three layers of material, two layers of which are heat sealed together so that a variety of tortuous pathways are formed. This assembly is then sealed to the third upper layer which extends around the perimeter of the wrap to form an inflatable cuff. A commutation between the end of the tortuous pathway and the inside of the outer layer exists to allow the expanded cooling agent to inflate the cuff. A valve on the upper surface may be adjusted to allow more or less gas to escape so that a desired compression of the wrap may be achieved. Velcro type attachment strips are used to secure the wrap around the injured limb.
However, when secured around the injured limb, the pressure in the inflated cuff closes off the tortuous pathway creating cold spots at various locations depending upon the contour of the limb being treated. When the valve is opened to reduce the pressure so that the tortuous pathway is unobstructed, the compression developed is insufficient to immobilize the area. The valves employed are comprised of numerous parts which, though inexpensive in their components, are expensive to assemble. They are also subject to intentional and inadvertent manipulation by the user so that, in practice, the pressure is often either above or below the doctors' recommended setting and varies during the treatment period. In addition, the device includes a plurality of baffles which extend into the tortuous pathway from the sealed sides in a direction counter to that of the flow through the pathway. These baffles trap small pockets of gas causing temperature variations over the surface of the device.
Finally, modifications to the design of compression wraps produced by the method shown in U.S. Pat. No. 3,871,381 are difficult and expensive to execute. These compression wraps are produced by sealing a variety of tortuous pathways and external configurations to achieve all-over cooling, localized cooling and specialized cooling of certain parts of the body. Each configuration requires a different sealing die which is very expensive to produce and mount onto the sealing equipment. Production of a variety of specialized wraps requires a large inventory of these expensive sealing dies.
Thus, there is a need for a device which provides portable, immediate cold and compression therapy and which provides a temperature and pressure which are uniform across the injured area and during the entire treatment period.